ode violation or not?

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electricaldoc

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210.4 Multiwire Branch Circuits.
(B) Dwelling Units. In dwelling units, a multiwire branch circuit supplying more than one device or equipment on the same yoke shall be provided with a means to disconnect simultaneously all ungrounded conductors at the panelboard where the branch circuit originated.

Would his apply to industry, and different voltages? If not is it a code requirement?

For example at my work I worked on a heater system. Where the power for heater comes from Hard wired 480V wye panelboard from several hundred feet away, and is ran threw emt. The control voltage 120v is supplied from a cord and plug. Which is dropped right out of the ceiling from soo cord from j box with EMT ran to 120V panelboard from several hounded feet the other direction. All power comes together in control box.

Now I can unplug 120v, and lock out 480v circuit breaker and all dead at once. So safe to work on, but is this a violation of code? If so which one?

Thanks in advance
Dan
 
Re: ode violation or not?

This doesn't sound safe to me. The 120v feed from another panel. The control can be feed from a small control transformer in the panel so when the 480v disconnect is locked out it will also kill your 120v control power. Makes it easy and safer, not so many disconnects to remember. Also you should have an sop on how to de-energize equipment properly.
 
Re: ode violation or not?

To: electricaldoc, To answer your question, is this a code violation, and the answer is NO, it is not a code violation. It is a very poor and unsafe situation.
shartVVV, mentioned a way to make the heater system that you work on very safe. To have a control transformer primary that would be turned off when you locked out your 480 volts. This is the way any good designer would design a system.
Now, if you are not going to do this, the minimum thing that should be done is to put signs indicating that you have 120 control volts feeding from another source than the 480 volts that you locked out.
 
Re: ode violation or not?

It is not uncommon at all for equipment to have more than one source of power.

There is a code rule that is applicable to this installation.

422.30 General.
A means shall be provided to disconnect each appliance from all ungrounded conductors in accordance with the following sections of Part III. If an appliance is supplied by more than one source, the disconnecting means shall be grouped and identified.
Click to expand...
IMO it is not unsafe, this is why having only trained personal working on electrical equipment is important.

I do agree a simple sign stating "More than one source of power supplying this equipment" would be a great idea. The signage may even be required by codes other than the NEC. :)
 
Re: ode violation or not?

So all though I recommend to my work that they should use a transformer from 480v to generate 120V control voltage this issue can not be forced.

My biggest worry is some of our so called qualified personnel do not even know how to use meter properly, and one of them was almost killed by trying to tighten down a live lug on the wrong side of disconnect with ratchet and socket.
 
Re: ode violation or not?

Some companies will fire personnel for not following proper proceedures. Especially lock-out tag-out proceedures. If your company doesn't force the issue, you may have to inform osha before someone gets hurt..
 
Re: ode violation or not?

He did fallow lock out tag out. It is just that he was suppose to be working on the other side of disconnect. Even after you lock it out main coming in to disconnect is live, and that is what he tried to tighten: :eek:
 
Re: ode violation or not?

Way back when I was a baby electrician the first thing I was taught was to test all circuits/wires.Treat all as if alive.I hate getting blasted and by following these rules I have avoided the test
 
Re: ode violation or not?

Ok sometimes I failed that test.....
 
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